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Tearless onions in development Down Under

Dr. Colin Eady, a Crop & Food Research scientist from New Zealand, plus fellow collaborators in Japan are testing tearless onions in the laboratory and recently presented their results during the 5th International Symposium on Edible Alliaceae, held in the Netherlands.

Dr. Colin Eady, a Crop & Food Research scientist from New Zealand, plus fellow collaborators in Japan are testing tearless onions in the laboratory and recently presented their results during the 5th International Symposium on Edible Alliaceae, held in the Netherlands.

Dr. Eady describes “tearless” onions as being in the developmental stages but if the research progresses well, the vegetables could become the household and industry norm within the next decade.

“We have been using a gene-silencing technology – called RNAi – that allows us to retarget the plant’s own natural regulation system without expressing foreign proteins in the plant,” explains Dr. Eady.

“Through RNAi, genes can be specifically shut down or turned off. By shutting down the lachrymatory factor synthase gene, we have stopped valuable sulphur compounds being converted to the tearing agent, and instead made them available for redirection into compounds, some of which are known for their flavour and health properties.”

The research team has been unable to induce tearing by crushing their model tearless onions, says Dr. Eady.

“What we have now is a truly unique germplasm with a unique trait. We can home in and study what the consequences of this one effect are. We can detect differences in sulphur compounds known to be involved in flavour and health and actually measure them and assign to them a role.”

Dr. Eady says he is most interested in sustainable and efficient production and wants to be sure the onions he is working on are capable of being grown in an efficient manner.

“We have a burgeoning population to feed, and with climate change and other challenges, available resources are being reduced,” he says. “The gene silencing system can also be used to combat virus diseases and biotechnology in general can help us produce more robust crops.”